U.S. patent application number 13/866414 was filed with the patent office on 2013-09-19 for ozonolysis reactions in liquid co2 and co2-expanded solvents.
This patent application is currently assigned to ARCHER DANIELS MIDLAND COMPANY. The applicant listed for this patent is ARCHER DANIELS MIDLAND COMPANY, UNIVERSITY OF KANSAS. Invention is credited to Thomas P. Binder, Daryle Busch, Andrew M. Danby, Bala SUBRAMANIAM.
Application Number | 20130240781 13/866414 |
Document ID | / |
Family ID | 40588806 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130240781 |
Kind Code |
A1 |
SUBRAMANIAM; Bala ; et
al. |
September 19, 2013 |
Ozonolysis Reactions in Liquid CO2 and CO2-Expanded Solvents
Abstract
A method for increasing ozone concentration in a liquid can
include: providing a gas having ozone; introducing the
ozone-containing gas into a liquid, wherein the liquid and ozone
combination has a temperature between about 0.8 and about 1.5 times
the critical temperature of ozone; and increasing isothermally, the
pressure of the ozone-containing gas above the liquid to about 0.3
to about 5 times the critical pressure of ozone so as to increase
the ozone concentration in the liquid. The temperature is expressed
in absolute units (Kelvin or Rankin). The method can be used for
removing ozone from a gas or for purifying ozone. The liquid having
a high ozone concentration can be used for ozonolysis of a
substrate.
Inventors: |
SUBRAMANIAM; Bala;
(Lawrence, KS) ; Busch; Daryle; (Lawrence, KS)
; Danby; Andrew M.; (Lawrence, KS) ; Binder;
Thomas P.; (Decatur, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UNIVERSITY OF KANSAS
ARCHER DANIELS MIDLAND COMPANY |
Lawrence
Decatur |
KS
IL |
US
US |
|
|
Assignee: |
ARCHER DANIELS MIDLAND
COMPANY
Decatur
IL
UNIVERSITY OF KANSAS
Lawrence
KS
|
Family ID: |
40588806 |
Appl. No.: |
13/866414 |
Filed: |
April 19, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12264446 |
Nov 4, 2008 |
8425784 |
|
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13866414 |
|
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60985407 |
Nov 5, 2007 |
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Current U.S.
Class: |
252/182.32 |
Current CPC
Class: |
B01D 2256/14 20130101;
C07D 323/02 20130101; C07C 51/34 20130101; C07D 501/14 20130101;
C07C 45/40 20130101; C07C 67/333 20130101; C07C 37/50 20130101;
C01B 13/10 20130101; C07C 303/02 20130101; Y02P 20/50 20151101;
C07D 311/78 20130101; B01D 53/1493 20130101; C01B 13/00 20130101;
Y02P 20/514 20151101; B01D 2257/106 20130101; Y02P 20/51 20151101;
C07C 45/40 20130101; C07C 47/02 20130101; C07C 45/40 20130101; C07C
47/542 20130101; C07C 45/40 20130101; C07C 47/54 20130101; C07C
45/40 20130101; C07C 49/185 20130101; C07C 45/40 20130101; C07C
47/575 20130101; C07C 45/40 20130101; C07C 47/46 20130101; C07C
45/40 20130101; C07C 49/04 20130101; C07C 51/34 20130101; C07C
53/08 20130101; C07C 51/34 20130101; C07C 63/06 20130101; C07C
51/34 20130101; C07C 53/126 20130101; C07C 67/333 20130101; C07C
69/48 20130101; C07C 67/333 20130101; C07C 69/716 20130101; C07C
303/02 20130101; C07C 309/08 20130101; C07C 37/50 20130101; C07C
39/04 20130101 |
Class at
Publication: |
252/182.32 |
International
Class: |
C01B 13/00 20060101
C01B013/00 |
Claims
1.-8. (canceled)
9. A method for increasing ozone concentration in a liquid, the
method comprising: providing a gas having ozone; introducing the
ozone-containing gas into the liquid to form a liquid and ozone
combination, wherein the liquid and ozone combination has a
temperature between about 0.8 and about 1.5 times the critical
temperature of ozone wherein the temperature is expressed in
absolute units and a pressure between about 0.3 to 5 times the
critical pressure of ozone, wherein the ozone is sharply compressed
to selectively dissolve into the liquid while background gases do
not display a sharp increase in compressibility.
10. The method as in claim 9, wherein said liquid and ozone
combination has a temperature between about 0.9 and about 1.35
times the critical temperature of ozone.
11. The method as in claim 9, wherein said liquid and ozone
combination has a temperature between about 0.95 and about 1.25
times the critical temperature of ozone.
12. The method as in claim 9, wherein said liquid and ozone
combination has a temperature between about 1 and about 1.2 times
the critical temperature of ozone.
13. The method as in claim 9, wherein said liquid and ozone
combination has a pressure between about 0.5 to about 2 times the
critical pressure of ozone.
14. The method as in claim 9, wherein said liquid and ozone
combination has a pressure between about 0.75 to about 1.5 times
the critical pressure of ozone.
15. The method as in claim 9, wherein said liquid and ozone
combination has a pressure between about 0.9 to about 1.35 times
the critical pressure of ozone.
16. The method as in claim 9, wherein said liquid and ozone
combination has a pressure between about 0.95 to about 1.25 times
the critical pressure of ozone.
17. The method as in claim 9, further comprising the step of
increasing, isothermally, the pressure of the ozone to about 0.3 to
about 5 times the critical pressure of ozone so as to increase the
ozone concentration in the liquid.
18. The method as in claim 9, further comprising the step of
increasing, isothermally, the pressure of the ozone to about 0.5 to
about 2 times the critical pressure of ozone so as to increase the
ozone concentration in the liquid.
19. The method as in claim 9, further comprising the step of
increasing, isothermally, the pressure of the ozone to about 0.75
to about 1.5 times the critical pressure of ozone so as to increase
the ozone concentration in the liquid.
20. The method as in claim 9, further comprising the step of
increasing, isothermally, the pressure of the ozone to about 0.9 to
about 1.35 times the critical pressure of ozone so as to increase
the ozone concentration in the liquid.
21. The method as in claim 9, further comprising the step of
increasing, isothermally, the pressure of the ozone to about 0.95
to about 1.25 times the critical pressure of ozone so as to
increase the ozone concentration in the liquid.
22. The method as in claim 9 wherein said providing step comprises
providing a gas having ozone at a temperature between about 0.8 and
1.5 times the critical temperature of ozone and increasing
isothermally the pressure to about 0.3 to 0.5 times the critical
pressure of ozone.
23. The method as in claim 9 wherein said providing step comprises
providing a gas having ozone at a temperature between about 0.9 and
1.35 times the critical temperature of ozone and increasing
isothermally the pressure to about 0.5 to 0.2 times the critical
pressure of ozone.
24. The method as in claim 9, wherein the ozone concentration in
the liquid is increased at least about 5 times.
25. The method as in claim 9, wherein the ozone concentration in
the liquid is increased to about an order of magnitude.
26. The method as in claim 9, further comprising providing
ultrasonic agitation to the liquid and ozone.
27. The method as in claim 9, wherein the liquid is comprised of
liquid carbon dioxide, light hydrocarbons (C.sub.4 or lower),
methanol, ethanol, alcohols, hexane, SF.sub.6, xenon, fluorocarbon
solvents, highly oxygenated molecules, highly fluorinated
molecules, CF.sub.3CO.sub.2H, ionic liquids, strong liquid acids,
H.sub.2SO.sub.4, HSO.sub.3F, HSO.sub.3CF.sub.3, organic acids,
saturated hydrocarbons, or combinations thereof.
28. The method as in claim 9, wherein the liquid is a carbon
dioxide expanded liquid comprised of light hydrocarbons (C.sub.4 or
lower), methanol, ethanol, alcohols, hexane, SF.sub.6, xenon,
fluorocarbon solvents, highly oxygenated molecules, highly
fluorinated molecules, CF.sub.3CO.sub.2H, ionic liquids, strong
liquid acids, H.sub.2SO.sub.4, HSO.sub.3F, HSO.sub.3CF.sub.3,
organic acids, saturated hydrocarbons, or combinations thereof.
29. The method as in claim 9 wherein the liquid is liquid carbon
dioxide and wherein the liquid carbon dioxide and ozone combination
has an absorption band at .lamda..sub.max at about 253.7 nm and at
about 577 nm and 603 nm, wherein at least one of the
.lamda..sub.max has an absorbance unit of about 0.005 when the
pressure is below about 0.5 times the critical pressure of ozone
and the .lamda..sub.max has an absorbance unit of about 0.01 to
about 0.1 when the pressure is between about 0.5 to about 2 times
the critical pressure of ozone.
30. The method as in claim 9 wherein the liquid is a carbon
dioxide-expanded solvent and wherein the carbon dioxide-expanded
organic solvent and ozone combination has an absorption band at
.lamda..sub.max at about 253.7 nm and at about 577 nm and 603 nm,
wherein at least one of the .lamda..sub.max has an absorbance unit
of about 0.005 when the pressure is below about 0.5 times the
critical pressure of ozone and the .lamda..sub.max has an
absorbance unit of about 0.01 to about 0.1 when the pressure is
between about 0.5 to about 2 times the critical pressure of
ozone.
31. The method as in claim 9, wherein the liquid is a carbon
dioxide-expanded liquid.
32. The method as in claim 9, wherein the liquid is liquid carbon
dioxide.
33. The method as recited in claim 32, wherein said liquid carbon
dioxide and ozone combination has a pressure between about 0.75 to
about 1.5 times the critical pressure of ozone.
34. The method as recited in claim 32, wherein said liquid carbon
dioxide and ozone combination has a temperature between about 0.9
to about 1.35 times the critical temperature of ozone and a
pressure between about 0.9 to about 1.35 times the critical
pressure of ozone.
35. The method as recited in claim 32, wherein said liquid carbon
dioxide and ozone combination has a temperature between about 0.95
to about 1.25 times the critical temperature of ozone and a
pressure between about 0.95 to about 1.25 times the critical
pressure of ozone.
36. The method as recited in claim 32, wherein said liquid carbon
dioxide and ozone combination has a temperature between about 1 to
about 1.15 times the critical temperature of ozone and a pressure
between about 1 to about 1.15 times the critical pressure of
ozone.
37. The method as in claim 32, wherein the liquid carbon dioxide
and ozone combination has a temperature between about 0.9 to 1.3
times the critical temperature of ozone wherein the temperature is
expressed in absolute units and a pressure above about 40.5
bar.
38. The method as in claim 9 wherein said gas having ozone is air
or an oxygen gas having ozone.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 12/264,446, filed on Nov. 4, 2008, which is
now issued as U.S. Pat. No. 8,425,784, which is a Non-Provisional
of U.S. Provisional Application Ser. No. 60/985,407, filed Nov. 5,
2007, both of which is incorporated herein by reference in their
entirety.
BACKGROUND
[0002] Ozonolysis reactions have been traditionally performed by
bubbling O.sub.3 through either an aqueous phase or an organic
liquid phase containing a substrate to be chemically modified, such
as molecules containing carbon-carbon double bonds (i.e., C.dbd.C).
The conventional methods, however, have several drawbacks. Firstly,
since O.sub.3 is highly reactive, the reaction temperatures
employed are typically sub-ambient (often around 0.degree. C.),
wherein the O.sub.3 solubility in the liquid phase is low albeit
typically greater than the solubility of dioxygen. For example, the
O.sub.3 solubility in water is 0.105.times.10.sup.-2 g/mL at 0+ C.
and 1.013 bar pressure. Secondly, the O.sub.3 reacts with many
traditional organic solvents, which not only decreases O.sub.3
availability for oxidizing the substrate, but also results in the
formation of undesired products (e.g., waste) arising from solvent
oxidation and increased solvent usage. Thirdly, the O.sub.3
solubility in the liquid phase is not sensitively tunable with
pressure, which often limits the ability to control reaction rate
and product selectivity.
[0003] Thus, it would be beneficial to have a process and reaction
conditions for performing ozonolysis with increased O.sub.3
solubility in the solvent. Additionally, it would be beneficial to
have a process and reaction conditions for performing ozonolysis in
a solvent that is substantially inert with respect to O.sub.3 so as
to limit the number and amount of unfavorable side products.
Further, it would be beneficial to have a process and reaction
conditions for performing ozonolysis where the O.sub.3 solubility
in the liquid phase is tunable with pressure so as to provide the
ability to control reaction rate and product selectivity.
SUMMARY
[0004] In one embodiment, the present invention includes a method
for increasing ozone concentration in a liquid. Such a method can
include: providing a gas having ozone; introducing the
ozone-containing gas into a liquid, wherein the liquid and ozone
combination has a temperature between about 0.8 and about 1.5 times
the critical temperature of ozone; and increasing isothermally, the
pressure of the ozone-containing gas above the liquid to about 0.3
to about 5 times the critical pressure of ozone so as to increase
the ozone concentration in the liquid. Also, the temperature can be
between about 1 to about 1.2 times the critical temperature of
ozone, wherein the temperature is expressed in Kelvin.
Additionally, the pressure can be increased to about 0.5 to about 2
times the critical pressure of ozone, wherein the pressure is
expressed in bars. The ozone concentration in the liquid is
increased at least about 5 times, above half an order of magnitude,
or to about an order of magnitude higher. Of course, the
temperature and pressure ranges can be converted and expressed in
other units.
[0005] In one embodiment, the liquid can include any of liquid
carbon dioxide, liquid light hydrocarbons (e.g., C.sub.4 or less),
methanol, ethanol, alcohols, hexane, liquid SF.sub.6, liquid xenon,
water, fluorocarbon solvents, highly oxygenated molecules, highly
fluorinated molecules, CF.sub.3CO.sub.2H, ionic liquids, strong
liquid acids, H.sub.2SO.sub.4, HSO.sub.3F, HSO.sub.3CF.sub.3,
organic acids, saturated hydrocarbons, or combinations thereof.
Also, the liquid can be a carbon dioxide expanded liquid of the
foregoing liquids.
[0006] In one embodiment, the present invention can include a
method for extracting ozone from a gas. Such a method can include:
providing a gas having ozone at a temperature between about 0.8 and
about 1.5 times the critical temperature of ozone; increasing
isothermally, the pressure of the ozone to about 0.3 to about 5
times the critical pressure of ozone; and introducing the
compressed ozone into a liquid, wherein the liquid and ozone
combination has a temperature between about 0.8 and about 1.5 times
the critical temperature of ozone and the pressure of the liquid
and ozone combination is about 0.3 to about 5 times the critical
pressure of ozone. The temperature and pressures can be as
described herein. Also, the liquids and carbon dioxide expanded
liquids can be as described herein.
[0007] In one embodiment, the present invention can include a
method of performing ozonolysis on a molecule in a liquid. Such a
method can include: providing a composition having a liquid and
ozone, wherein the liquid and ozone composition has a temperature
between about 1 to about 1.2 times the critical temperature of
ozone and a pressure between about 0.5 to about 2 times the
critical pressure of ozone, wherein the molecule is dissolved or
dispersed in the liquid; and reacting the molecule with the ozone.
The method can further include introducing the molecule into one of
the following: the liquid before the ozone; the ozone before the
liquid; or the liquid and ozone combination. The temperature and
pressures can be as described herein. Also, the liquids and carbon
dioxide expanded liquids can be as described herein.
[0008] In one embodiment, the ozonolysis can further include:
introducing the ozone into the liquid, wherein the liquid and ozone
combination has a temperature between about 0.8 and about 1.5 times
the critical temperature of ozone; and increasing, isothermally,
the pressure of the ozone in the liquid to about 0.3 to about 5
times the critical pressure of ozone so as to increase the ozone
concentration in the liquid.
[0009] In one embodiment, the molecule undergoing ozonolysis can be
selected from the group consisting of a molecule having an
unsaturated hydrocarbon, a molecule having a carbon-carbon double
bond, unstaturated hydrocarbon acids, methyl oleate, oils, fats,
soybean oil, unstaturated fatty acids, vegetable fatty acids,
esters of fatty acids, fatty acid amides, alkenes, steroids,
benzylics, a molecule having an allylic moiety, terpenes,
cephalosporin, cephalosporin derivatives, a tertiary allylic
alcohol, and the like.
[0010] In one embodiment, the present invention can include a fluid
composition for performing ozonolysis on a molecule that has a
combination of a liquid, such as liquid carbon dioxide or a carbon
dioxide expanded liquid, and ozone having a temperature between
about 1 to about 1.2 times the critical temperature of ozone and a
pressure between about 0.5 to about 2 times the critical pressure
of ozone. The composition can also include the molecule undergoing
ozonolysis. The temperature and pressures can be as described
herein. Also, the liquids and carbon dioxide expanded liquids can
be as described herein.
[0011] In one embodiment, the fluid composition can be
characterized by having an absorption band at .lamda..sub.max at
about 253.7 nm and at about 577 nm and 603 nm, wherein at least one
of the .lamda..sub.max has an absorbance unit of about 0.005 units
when the pressure is below about 0.5 times the critical pressure of
ozone and the .lamda..sub.max has an absorbance unit of about 0.01
to about 0.1 when the pressure is between about 0.5 to about 2
times the critical pressure of ozone.
[0012] In one embodiment, the present invention can include a
method for separating ozone from air or an oxygen gas having the
ozone. Such a method can include: providing a gas comprising ozone
having a temperature above the critical temperature of ozone and a
pressure below the critical pressure of ozone; changing the
temperature of the gas to a temperature to about or less than the
critical temperature of ozone; and increasing the pressure of the
gas to about the critical pressure of ozone so as to separate the
ozone from the gas. The temperature and pressures can be as
described herein. Also, the liquids and carbon dioxide expanded
liquids can be as described herein. Optionally, the gas is in the
presence of a liquid and the ozone separates from the gas into the
liquid.
[0013] These and other embodiments and features of the sensor
device will become more fully apparent from the following
description and appended claims, or may be learned by the practice
of the sensor device as set forth hereinafter.
[0014] The foregoing summary is illustrative only and is not
intended to be in any way limiting. In addition to the illustrative
aspects, embodiments, and features described above, further
aspects, embodiments, and features will become apparent by
reference to the drawings and the following detailed
description.
FIGURES
[0015] To further clarify the above and other advantages and
features of the ozonolysis reactor device and compositions of the
feed and reaction mixtures, an illustrative description of the
ozonolysis reactor device will be rendered by reference to the
appended drawings. It is appreciated that these drawings depict
only illustrated embodiments of the ozonolysis reactor device and
are therefore not to be considered limiting of its scope. As such,
the figures should not be construed to be limiting any object in
shape or size and the features of the present invention, such as
the ozonolysis reactor device, can have various shapes and sizes as
needed or determined.
[0016] FIGS. 1A-1C are schematic representations of ozonolysis
reactions (Kirk-Othmer Encyclopedia of Chemical Technology 4.sup.th
Edition, John Wiley and Sons, New York 8 124-125 (1996)).
[0017] FIGS. 2A-2E are schematic representations of ozonolysis
reactions.
[0018] FIG. 3 is a schematic diagram of a system for performing
ozonolysis or purifying ozone from a gas.
[0019] FIGS. 4A-4B are graphs showing the UV/Visible spectrum of
ozone, which has the strong absorption Hartley Band and the weak
absoption Chappuis Band.
[0020] FIG. 5 is a graph showing the increase in absorption in the
Chappuis Band as ozone is added (by pressurization) to a fixed
volume of liquid CO.sub.2.
[0021] FIG. 6 is a graph showing ozone concentration vs P.sub.total
as ozone/air or ozone/oxygen mixtures are added (by pressurization)
to a fixed volume of liquid CO.sub.2.
[0022] FIG. 7 is a graph showing the increase in absorption in the
Chappuis Band as ozone is added to liquid carbon dioxide.
[0023] FIG. 8 is a graph showing ozone concentration vs P.sub.total
as ozone is added to liquid CO.sub.2.
[0024] FIG. 9 is a graph showing the effect of temperature on the
CO.sub.2 expansion of methanol/soybean oil binary (molar ratio of
6:1).
[0025] FIG. 10 is a graph showing the UV/Visible spectra of CXL
methanol as ozone is added.
[0026] FIG. 11 is a graph showing the UV/Visible spectra of CXL
hexane as ozone is added.
[0027] FIG. 12 is a graph showing the UV/Visible spectra of liquid
methanol at 1.013 bar as ozone is added.
[0028] FIG. 13 is a graph showing the UV/Visible spectra of
ozonated methanol as methyl oleate is added.
[0029] FIG. 14 is a graph showing the UV/Visible spectra of methyl
oleate in methanol as ozone is added.
[0030] FIG. 15 is a graph showing a measure of ozone solubility in
water as a function of pressure under isothermal conditions when
the temperature is 2.degree. C.
[0031] FIG. 16 is a graph showing a measure of ozone solubility in
water as a function of pressure under isothermal conditions when
the temperature is 6.degree. C.
[0032] FIG. 17 is a graph showing a measure of ozone solubility in
water as a function of pressure under isothermal conditions when
the temperature is 20.degree. C.
[0033] FIG. 18 is a schematic diagram of a system that has an
ultrasonic probe for causing ultrasonic agitation during ozonolysis
or when purifying ozone from a gas.
[0034] FIG. 19 is a graph showing the rate of ozone decomposition
in water with and without ultrasonic agitation (Kang, J-W., Lee,
K-H., Koh, C-I., Nam, S-N., Korean Journal of Chemical Engineering
18 336 (2001)).
[0035] FIG. 20 is a table showing the effects of ultrasonic
agitation on the rate constants for ozone decomposition in water
and in liquid carbon dioxide.
DETAILED DESCRIPTION
[0036] In the following detailed description, reference is made to
the accompanying drawings, which form a part hereof. In the
drawings, similar symbols typically identify similar components,
unless context dictates otherwise. The illustrative embodiments
described in the detailed description, drawings, and claims are not
meant to be limiting. Other embodiments may be utilized, and other
changes may be made, without departing from the spirit or scope of
the subject matter presented here.
I. Introduction
[0037] Generally, the present invention includes novel processes
for increasing ozone concentrations in liquids and for performing
ozonolysis reactions. Ozone has a critical temperature (T.sub.c) of
-12.15.degree. C. (261 K), a critical pressure (P.sub.c) of 55.73
bar (CHECK), and a critical density (.rho..sub.c) of 540
kg/m.sup.3. In the ozonolysis process, the substrate (e.g.,
molecule containing C.dbd.C) is either dissolved or emulsified in
liquid carbon dioxide or carbon dioxide-expanded solvents. In order
to increase ozone concentrations in liquids, ozone (O.sub.3)
containing gas stream, produced using either air or oxygen in an
ozone generator, is added to the liquid phase (e.g., liquid carbon
or carbon dioxide-expanded solvents) at temperatures preferably
between about 1-1.2 times the critical temperature of O.sub.3
(expressed in K). The ozone is compressed to pressures preferably
between about 0.5-2 times the critical pressure of O.sub.3.
Solubility of O.sub.3 in liquid CO.sub.2 has been determined to
increase by nearly an order of magnitude when the pressure is
increased from approximately 51 to 65 bar. Under these conditions,
it has been shown that the O.sub.3 is stable when mixed with liquid
CO.sub.2, and the O.sub.3 can cleave carbon-carbon double bonds in
substrates, especially such as those in the context of the
bio-refinery, producing building blocks for synthesis of a variety
of industrial chemicals. The reaction proceeds via intermediates
that are meta-stable, but further oxidation or reduction subsequent
to the primary ozone oxidation produces molecules of lower mass,
which are commonly suitable as building blocks for chemical
synthesis. As an example, it has now been shown that ozonolysis of
methyl oleate,
CH.sub.3(CH.sub.2).sub.7CH.dbd.CH(CH.sub.2).sub.7C(.dbd.O)OCH.sub.3,
in liquid CO.sub.2 and CO.sub.2-expanded liquids, produces
carboxylic acids, dicarboxylic acids, and aldehydes.
[0038] The ozonolysis process of the present invention may be
employed to cleave carbon-carbon double bonds in substrates,
especially such as those in the context of the bio-refinery,
producing building blocks for synthesis of a variety of industrial
chemicals. The reaction proceeds via intermediates that are
meta-stable, but further oxidation or reduction subsequent to the
primary ozone oxidation produces molecules of lower mass, suitable
as building blocks for chemical synthesis. In liquid CO.sub.2,
ozone density increases significantly close to its critical point,
which allows for increasing the solubility of ozone and the
capability of tuning the ozone concentration in the liquid phase
for a particular purpose. Also, ozone preferentially oxidizes many
olefinic substrates in CO.sub.2 and CXL. For methyl oleate
ozonation, the solvent system produces the following: In CO.sub.2,
nonanal, nonanoic acid, and nonanedoic acid are produced; In
CO.sub.2 expanded hexane, nonanol, nonanoic acid, nonanedoic acid
are produced; and in CO.sub.2 expanded methanol, nonanedoic acid
and nonanoic acid are produced.
[0039] The significant characteristics of the new process are as
follows: (i) The O.sub.3 is stable in the preferred solvent due to
its non-reactivity at preferred reaction conditions; (ii) At the
preferred reaction temperatures, the O.sub.3 solubility in the
solvent may be increased by about an order of magnitude with
relatively small changes in pressure. This tunability provides an
ability to control reaction rates and product selectivity; (iii)
Reduced flammability hazards; (iv) Low toxicity of solvent; (v)
Facile product separation.
[0040] Because of its high oxidation potential (E.degree.2.075 V in
acid and 1.246 V in base), ozone has been investigated as a
powerful and environmentally benign oxidant in that it eventually
decomposes to atmospheric oxygen. For example, ozonolysis of methyl
oleate,
CH.sub.3(CH.sub.2).sub.7CH.dbd.CH(CH.sub.2).sub.7C(.dbd.O)OCH.sub.3,
followed by catalytic reduction in water gives yields of aldehydes
approaching 90%. Detailed study of the meta-stable initial
oxidation products has shown that 90% of the methyl oleate is
transformed to 1,2,4-trioxolane, and 10% yield to peroxide
oligomers (FIG. 1A). The latter should be accompanied by an
equivalent molar amount of an aldehyde. The 1,2,4 trioxolane is
formed by rearrangement of the initial product of 1,3 addition of
ozone to the double bond, the 1,2,3-trioxolane. That rearrangement
is understood to occur via a reversible dissociative process into
an aldehyde and a zwitterionic peroxide. FIG. 1B shows the reaction
scheme, which is expanded to display the complexity of
intermediates that this dissociative process generates.
[0041] Despite the likelihood of seven or so intermediates (not
counting geometric isomers), only a pair of products is formed, the
aldehyde and the carboxy ester aldehyde. Significantly, if the
ozonolysis reaction is followed by completion of the oxidation
process, the products are a carboxylic acid and a dicarboxylic acid
(FIG. 1C).
II. Ozonolysis
[0042] In one embodiment, the present invention provides improved
processes and reaction conditions for performing ozonolysis with
increased O.sub.3 solubility in the liquid solvent (i.e., liquid
medium). The processes and reaction conditions for performing
ozonolysis can include the use of a liquid solvent that is
substantially inert with respect to O.sub.3 so as to limit the
number and amount of unfavorable side products. The ozonolysis
process can be performed where the O.sub.3 solubility in the liquid
phase is tunable with pressure so as to provide the ability to
control reaction rate and product selectivity. Such processes and
reactions can be achieved through the use of liquid CO.sub.2
(P.sub.c, CO.sub.2=73.76 bar; T.sub.c, CO.sub.2=31.1.degree. C. or
304.25 K) or CO.sub.2-expanded liquids as the solvent medium.
[0043] In one embodiment, the ozonolysis can be performed with
liquid CO.sub.2 and various CO.sub.2 expanded solvent liquids, such
as natural unsaturated acids (e.g., oleic acid) or methyl esters
thereof. The reaction rate for ozonolysis is most likely limited by
the low solubility of ozone in the liquid phase. The use of
CO.sub.2 and CO.sub.2-expanded liquids (CXLs) as reaction media can
improve O.sub.3 solubility as well as provide an inert environment
for ozonolysis. In addition, non-flammable CO.sub.2 is also
miscible with low polarity solvents such as n-hexane. The
ozonolysis followed by an appropriate hydrolytic, reductive or
oxidative step can produce carboxylic acids, dicarboxylic acids,
terminal carboxy alcohols or carboxy aldehydes. Significantly,
similar results can be expected with other fatty acids having two
or three carbon-carbon double bonds.
[0044] In one embodiment, ozonolysis can be performed in liquid
CO.sub.2. It is shown herein that O.sub.3 is stable in liquid
CO.sub.2 and does not substantially react with CO.sub.2. The
solubility of O.sub.3 in liquid CO.sub.2 can be tuned continuously
(e.g., increasing solubility up to about an order of magnitude)
with relatively small changes in pressure around the critical
pressure of ozone. For example, the solubility of O.sub.3 in liquid
CO.sub.2 at -0.7.degree. C. (272.45 K) (e.g., 1.044 T.sub.c,
O.sub.3) was experimentally determined to be approximately 0.006
absorbance unit at 52.4 bar (0.94 P.sub.c, O.sub.3) and 0.06
absorbance unit at 65.5 bar (1.18 P.sub.c, O.sub.3). Thus, the
sensitive tunability of O.sub.3 solubility in liquid CO.sub.2 is
related to the extreme compressibility of O.sub.3 in the vicinity
of its critical point.
[0045] O.sub.3 is in the vicinity of its critical temperature
(i.e., between 1 and 1.25 T.sub.c, O.sub.3l) at -0.7.degree. C.
(272.45 K). Hence, ozone compressibility (and therefore its
density) will increase sharply as the pressure is isothermally
increased beyond its critical pressure (e.g., above about 55.6
bar). On the other hand, air and O.sub.2, which are the background
gases in the O.sub.3 stream at -0.7.degree. C. (272.45 K) are
sufficiently far removed from their respective critical
temperatures, and hence behave like ideal gases in the 50.6-66.9
bar pressure range, without displaying any sharp increase in
compressibility. As such, even though the O.sub.3 is present in
dilute concentrations, such as on the order of a few mole
percentage either in the air stream or in the O.sub.2 stream, its
compressibility, and therefore its density, increases sharply in
the vicinity of its critical pressure, causing it to selectively
dissolve in liquid CO.sub.2. This phenomenon is akin to the
increased dissolution of near-critical CO.sub.2 in organic solvents
as the pressure is increased beyond its critical pressure. Other
advantages of increasing ozone concentration in CO.sub.2 or
CO.sub.2-expanded liquids as the solvent medium are as follows: (i)
reduced flammability hazards due to the presence of dense CO.sub.2,
which is a flame retardant, in the gas phase; (ii) CO.sub.2 is less
toxic than most organic solvents; (iii) use of CO.sub.2 is
considered environmentally benign if it is derived from existing,
non-sequestered sources; and (iv) products can be easily separated
from CO.sub.2 solvent by pressure reduction.
[0046] The ozonolysis medium for the first step can be any liquid
CO.sub.2 at a variety of temperatures that are close to the
critical temperature of ozone. The temperature of the ozone in
liquid CO.sub.2 can be between 0.75 and 1.5 T.sub.c of ozone, more
preferably from about 0.9 to about 1.35 T.sub.c of ozone, and most
preferably from about 0.95 to about 1.25 T.sub.c of ozone.
Preferred temperatures of ozone in liquid CO.sub.2 can be about 1,
about 1.1, and about 1.15 T.sub.c of ozone. The temperature as a
function of the T.sub.c is expressed in absolute units (Kelvin or
Rankine); however, the temperature and temperature ranges can be
converted to other units.
[0047] The ozonolysis medium for the first step can be any liquid
CO.sub.2 at a temperature close to the critical temperature of
ozone and a suitable pressure close to the critical pressure. The
pressure of the ozone in liquid CO.sub.2 can be between 0.75 and
1.5 P.sub.c of ozone, more preferably from about 0.9 to about 1.35
P.sub.c of ozone, and most preferably from about 0.95 to about 1.25
P.sub.c of ozone. Preferred pressures of ozone in liquid CO.sub.2
can be about 1, about 1.1, and about 1.15 P.sub.c of ozone. Stated
differently, the pressure of the ozone in liquid CO.sub.2 can be
above about 40.5 bar, between about 45.6 bar and 76 bar, more
preferably from about 50.7 bar to about 65.9 bar, and most
preferably from about 54.7 bar to about 60.8 bar. Preferred
pressures of ozone in liquid CO.sub.2 can be about 52.7 bar, about
55.7 bar, and about 59.8 bar. The pressure as a function of Pc can
be expressed in atmospheres (atm) or bar, and appropriate unit
changes can be made for other pressure units.
[0048] The ozonolysis medium for the first step can be any liquid
CO.sub.2 having a variety of ozone densities that are close to and
preferably above the critical density of ozone. The density of
ozone can be between 0.75 and 1000 .rho..sub.c, more preferably
from about 0.9 to about 100 .rho..sub.c, and most preferably from
about 0.95 to about 10 .rho..sub.c of ozone.
[0049] The ozonolysis reaction is exothermic and the solvent can
moderate the reaction rate, and therefore the rate of heat
generation. Solvents, either inert or more inert compared to the
substrate, act as a heat sink to absorb the heat of reaction.
However, there are instances where a substrate can also be the
solvent when provided in an amount sufficient to function as the
solvent as well as provide sufficient substrate for the ozonolysis
reaction.
[0050] Ozonolysis can be conducted in liquid solvents such as
organic acids, alcohols, methylene chloride, ethyl acetate, THF,
and even water; however, they can produce an array of intermediate
peroxides. Water is desirable, but such reactions for higher
molecular weight acids and esters can require the use of biphasic
liquid systems. Alcohols are attractive because of good solubility
relationships and in part because the solvent can reflect the alkyl
group of the ester. The disadvantage of alcohols as solvents for
ozonolysis is their susceptibility to oxidation, a factor that can
present a hazard. In the present invention a solvent system such as
a carbon dioxide expanded liquid (CXL), generated with low
molecular weight alcohols, methanol and ethanol, can be used.
[0051] The effectiveness of the liquid solvents that are CXLs and
other CXLs in catalytic oxidations can be increased using pure
molecular oxygen. Their advantages include the high solubility of
O.sub.2 (e.g., as much as 100 fold over the organic solvent) and
the safety benefit of a medium that is non-combustible and that
will dominate the vapor phase in equilibrium with the reaction
medium. In addition to process intensification based on increased
oxidant solubility, molecular transport in CXLs is high compared to
most media. Further, CXLs based on polar alcohols display that
polarity in increased reaction rates compared to nonpolar media
such as supercritical CO.sub.2, or hydrocarbons.
[0052] Methanol-based CXLs can be used as a liquid medium for the
oxidative cleavage of the methyl ester of oleic acid and those of
higher unsaturated acids. Fatty acids such as palmitic acid exhibit
limited solubility in either methanol or supercritical CO.sub.2.
The solubility of palmitic acid in supercritical CO.sub.2 is on the
order of 10.sup.-4 mole fraction even at pressures up to 150 bar.
For example, soybean oil can also be used as a liquid medium for
ozonolysis. The emulsion disappears and the methanol/soybean oil
interface reappears when the CO.sub.2 is released. This observation
indicates the possibility of performing ozonolysis of fatty acid
substrates dispersed as emulsion in CO.sub.2-expanded methanol.
Thus, carbon dioxide expanded methanol appears to be extremely well
suited to ozone oxidation of the methyl esters of unsaturated acids
to produce difunctional molecules of lower molecular weight and of
significance as products of the bio-refinery. However, our results
show that O.sub.3 may attack methanol especially if the
concentration of methanol is substantially higher than the
substrate.
[0053] Some examples of solvents for a CXL that can be used for
ozonolysis include: light hydrocarbon (C.sub.4 or lower) liquids,
methanol, ethanol, lower alcohols (e.g., C.sub.4-C.sub.10), higher
alcohols (e.g., C.sub.10-C.sub.20) hexane, SF.sub.6, xenon, water,
aqueous solutions, fluorocarbon solvents, highly oxygenated
molecules, highly fluorinated molecules, CF.sub.3CO.sub.2H, ionic
liquids, strong liquid acids, H.sub.2SO.sub.4, HSO.sub.3F,
HSO.sub.3CF.sub.3, organic acids, saturated hydrocarbons, liquid
substrates for ozonolysis, combinations thereof, and the like. The
solubility of ozone in any of the aforementioned solvents can be
increased by preparing a CXL as described herein.
[0054] In some instances, it can be preferable for the solvent in a
CXL to be inert. Some examples of possible inert solvents for a CXL
that can be used for ozonolysis can include: SF.sub.6, xenon,
water, aqueous solutions, fluorocarbon solvents, highly oxygenated
molecules, highly fluorinated molecules, CF.sub.3CO.sub.2H,
H.sub.2SO.sub.4, HSO.sub.3F, and HSO.sub.3CF.sub.3.
[0055] Experiments have shown that some non-inert solvents may be
used if the O.sub.3 selectively attacks the substrate over the
solvent (such is the case when using methanol as a solvent
additive). That is, a liquid substrate can be used as a solvent in
instances where the substrate desired to be reacted is more
reactive with ozonolysis. This allows ozone to react more with the
desired substrate rather then the solvent (e.g., possible substrate
when used in inert or more inert solvents). For example, some
substrate candidates, such as vegetable oils including soybean oil,
which are known to be reactive with ozone can be used as solvents
when the desired substrate is more reactive in comparison. In this
context, the solvent is the more inert component of a
solvent-substrate system. Thus, the solvent is the liquid that is
either totally or substantially inert to ozone attack, or is less
preferentially attacked by ozone in the presence of a more reactive
substrate.
[0056] Some examples of possible non-inert solvents for a CXL that
can be used for ozonolysis can include: methanol, ethanol, lower
alcohols (e.g., C.sub.4-C.sub.10), higher alcohols (e.g.,
C.sub.10-C.sub.20) hexane, ionic liquids, liquid acids, organic
acids, and saturated hydrocarbons.
[0057] In one embodiment, the ozonolysis process of the present
invention can be used for oxidative cleavage of oils and fats, such
as unsaturated fatty acids. The double bonds in unsaturated fatty
acids provide reactive sites for performing a variety of
transformations. Accordingly, oxidative scission of olefins can be
obtained with ozonolysis. As shown in FIG. 2A, this highly
selective reaction initially forms an ozonide, which can go on
yield either aldehydes or carboxylic acids, with reductive or
oxidative workup, respectively. This method is particularly
attractive for producing carboxylic acids containing an odd number
of carbon atoms in the polymethylene backbone. For example,
industrially, azelaic acid is produced from oleic acid via
ozonolysis, and is used in the manufacture of plasticizers,
lubricants, hydraulic oils and cosmetics. It also is used as an
anti-bacterial in acne treatments. Potential substrates for this
ozonolysis reaction are extensive, and include fatty acids, their
esters, and other sources of oil and fats.
[0058] In one embodiment, the ozonolysis process can be used for
preparing ingredients and reagents for perfume and fragrance
chemistry. For example, ozonation of terpenes can be used to
preparing ingredients and reagents. Oxygenated compounds form the
bulk of most odiferous chemistry, so it is not surprising that the
ozonolytic fission of alkenes is used extensively in the perfume
and fragrance industries. There is an extensive chemistry
associated with the production of various fragrant molecules from
the terpenes, and the majority of synthetic routes begin with the
ozonolytic cleavage of an allylic moiety within the terpene
molecule. For example, ozonolysis of the terpene, (+)-p-menth-1-ene
can form, by reductive workup, (-)-3-isopropyl-6-oxoheptanal. This
molecule can then undergo a variety of reactions to form several
fragrant molecules (e.g., new mown hay, minty note, lily of the
valley, bergamot-like, rose/orange blossom, and the like) as shown
in FIG. 2B.
[0059] In one embodiment, the ozonolysis process can be used for
preparing active agents for pharmaceutical products or reagents for
making pharmaceutical products. Ozonolysis of suitable substrates,
such as natural products or bioactive agents, can be used to
prepare new bioactive agents or derivatives of various biological
active molecules. For example, oxandrolone is an anabolic steroid
used to promote weight gain in patients who have experienced
surgery, chronic infection or severe trauma. It also relieves bone
pain associated with osteoporosis. It was originally developed by
G.D. Searle Company and was synthesized from methylandrostanolone
via a multistep route involving the use of highly toxic OsO.sub.4
and Pb(OAc).sub.4. An alternative route for multi kilogram
quantities of USP Oxandrolone has been developed by Cedarburg
Pharmaceuticals, Inc., which utilizes an ozonolysis reaction to
produce a key intermediate acid in good yields while avoiding the
use of highly toxic, persistent reagents and the associated
problems with the accumulation of hazardous waste. As shown in FIG.
2C, the ozonolysis process of the present invention can be used to
prepare oxandrolone in a safer, more economical process.
[0060] In another example, the ozonolysis process of the present
invention can be used to prepare antibiotics, such as cefaclor and
ceftibuten, from suitable substrates. Cefaclor and ceftibuten are
compounds belonging to a class of medications called cephalosporin
antibiotics. They are effective against a wide range of infections
and were discovered by Shionogi and Co. Ltd., Osaka, Japan.
Originally they were produced synthetically from penicillin
sulfoxides, but attempts to reduce the cost of production by
scientists at the Schering Plough Research Institute have resulted
in synthetic routes from cephalosporin C broths. A key step in this
route is an ozonolysis step which converts the 3-exomethylene
cephalosporin (1) into 3-hydroxycephem (2). As shown in FIG. 2D,
the ozonolysis process of the present invention can be used to
prepare 3-hydroxycephem (2) in a safer, more economical
process.
[0061] In another example, the ozonolysis process of the present
invention can be used to prepare 2-Hydroxyindan-2-carboxaldehyde.
Pfizer previously developed a multi-kilogram scale synthesis for
the 2-indanone derived aldehyde, 2-hydroxyindan-2-carboxaldehyde,
which is used in a reductive amination reaction. 2-Indanone
undergoes a Grignard addition with vinylmagnesium bromide to yield
a tertiary allylic alcohol. This undergoes ozonolysis in methanol,
and subsequently the solvent traps the carbonyl oxide intermediate
to form the methoxy-hydroperoxide. The hydroperoxide is the reduced
with sodium bisulfite to form a stable bisulfite adduct which is
used in the reductive amination in preference to the aldehyde. As
shown in FIG. 2E, the ozonolysis process of the present invention
can be used to prepare 2-hydroxyindan-2-carboxaldehyde in a safer,
more economical process.
[0062] In one embodiment, the ozonolysis process of the present
invention can be useful for non-olefin oxidation reactions. For
example, the non-olefin oxidation reactions can be the oxidation of
benzylic substrates and the like via ozonolysis. Accordingly, the
chemistry of ozonolysis of organics substrates is not limited to
the selective cleavage of double bonds. It has been shown that
ozone can efficiently oxidize substituted benzylic compounds to
their corresponding benzaldehydes and benzoic acids using a
transition metal catalyst. As such, solvent and reaction conditions
described herein and using manganese(II) acetate as the catalyst,
the oxidation of toluene derivatives can be directed to either the
aldehyde or the carboxylic acid products. The only off-gas produced
is oxygen. The ozonolysis process of the present invention can be
used to prepare benzaldehydes and benzoic acids in a safer, more
economical process.
[0063] In one embodiment, the ozonolysis process of the present
invention can be used for the production of singlet oxygen. The
production of singlet oxygen from ozone has received some attention
recently. Conventional methods for production involve irradiating
oxygen gas with ultraviolet light in the presence of a sensitizer,
such as tetraphenylporphyrin. The presence of large quantities of
dioxygen, organic solvents and light, in addition to the costs of
special gas/liquid photoreactors, have discouraged industrial
application and limited the industrial use to small scale
applications in flavor and perfume production. Consequently, dark
methods of producing .sup.1O.sub.2 have been extensively
investigated, with the catalytic conversion of hydrogen peroxide by
molybdate being the most attractive. Ozone can also be used to
produce .sup.1O.sub.2 and it has been shown that
1,1'-bis(diphenylphosphino)ferrocene promotes splitting of ozone to
give Accordingly, the ozone in CO.sub.2 or CXL along with
1,1'-bis(diphenylphosphino)ferrocene can be used to produce
.sup.1O.sub.2. Also, by reductive recycling of (e.g.,
hydrogenating) the oxidized form of the ferrocene catalyst, a
continuous process can be conducted to produce .sup.1O.sub.2.
[0064] In one embodiment, the ozonolysis process of the present
invention can be used for the oxidation of methane. The enhanced
ozone solubility in CO.sub.2 or CXL can be used for the oxidation
of methane via ozonolysis. Previously, oxidation of methane has
been reported to transform methane to protonated formaldehyde in
super acid media. In such powerful acid solutions, methane has also
been reported to be oxidized, along with oligomerization, to
protonated acetone or to the related alkyl carbenium ion. Now, such
transformations can be performed with ozone in CO.sub.2 or CXL.
[0065] The ozonolysis process of the present invention can be
applied to a wide variety of substrates. The most common substrates
can be vegetable fatty acids, esters of fatty acids, fats and oils.
Examples of vegetable fatty acids are selected from the group
consisting of butyric acid, caproic acid, caprylic acid, capric
acid, lauric acid, myristic acid, palmitic acid, stearic acid,
arachic acid, behenic acid, lignoceric acid, hexacosanoic acid,
octacosanoic acid, triacontanoic acid and n-dotriacontanoic acid,
and those having an odd number of carbon atoms, such as propionic
acid, n-valeric acid, enanthic acid, pelargonic acid, hendecanoic
acid, tridecanoic acid, pentadecanoic acid, heptadecanoic acid,
nonadecanoic acid, heneicosanoic acid, tricosanoic acid,
pentacosanoic acid, heptacosanoic acid, isobutyric acid, isocaproic
acid, isocaprylic acid, isocapric acid, isolauric acid,
11-methyldodecanoic acid, isomyristic acid, 13-methyl-tetradecanoic
acid, isopalmitic acid, 15-methyl-hexadecanoic acid, isostearic
acid, 17-methyloctadecanoic acid, isoarachic acid,
19-methyl-eicosanoic acid, .alpha.-ethyl-hexanoic acid,
.alpha.-hexyldecanoic acid, .alpha.-heptylundecanoic acid,
2-decyltetradecanoic acid, 2-undecyltetradecanoic acid,
2-decylpentadecanoic acid, 2-undecylpentadecanoic acid, Fine oxocol
1800 acid (product of Nissan Chemical Industries, Ltd.),
6-methyl-octanoic acid, 8-methyl-decanoic acid,
10-methyl-dodecanoic acid, 12-methyl-tetradecanoic acid,
14-methyl-hexadecanoic acid, 16-methyl-octadecanoic acid,
18-methyl-eicosanoic acid, 20-methyl-docosanoic acid,
22-methyl-tetracosanoic acid, 24-methyl-hexacosanoic,
26-methyloctacosanoic acid, including 4-decenoic acid, caproleic
acid, 4-dodecenoic acid, 5-dodecenoic acid, lauroleic acid,
4-tetradecenoic acid, 5-tetradecenoic acid, 9-tetradecenoic acid,
palmitoleic acid, 6-octadecenoic acid, oleic acid, 9-octadecenoic
acid, 11-octadecenoic acid, 9-eicosenoic acid, cis-11-eicosenoic
acid, cetoleic acid, 13-docosenoic acid, 15-tetracosenoic acid,
17-hexacosenoic acid, 6,9,12,15-hexadecatetraenoic acid, linoleic
acid, linolenic acid (18:3 n3), gamma linolenic acid (18:3 n6),
.alpha.-eleostearic acid, gadoleic acid (20:1), .alpha.-eleostearic
acid, punicic acid, 6,9,12,15-octadecatetraenoic acid, parinaric
acid, 5,8,11,14-eicosatetraenoic acid, erucic acid,
5,8,11,14,17-eicosapentaenoic acid (EPA),
7,10,13,16,19-docosapentaenoic acid,
4,7,10,13,16,19-docosahexaenoic acid (DHA), .alpha.-hydroxylauric
acid, .alpha.-hydroxymyristic acid, .alpha.-hydroxypalmitic acid,
.alpha.-hydroxystearic acid, .omega.-hydroxylauric acid,
.alpha.-hydroxyarachic acid, 9-hydroxy-12-octadecenoic acid,
ricinoleic acid, .alpha.-hydroxybehenic acid,
9-hydroxy-trans-10,12-octadecadienic acid, kamolenic acid, ipurolic
acid, 9,10-dihydroxystearic acid, 12-hydroxystearic acid, oxalic
acid, citric acid, malonic acid, succinic acid, glutaric acid,
adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic
acid, D,L-malic acid, derivatives of any thereof, and combinations
of any thereof.
[0066] Examples of esters of fatty acids are selected from the
group consisting of methyl laurate, methyl myristate, methyl
palmitate, methyl oleate, methyl elaidate, methyl linoleate, methyl
linolenate, methyl stearate, methyl erucate, methyl ricinoleate,
methyl licanate, methyl elaeostearate, methyl arachidonate, methyl
clupanodonate, ethyl laurate, ethyl myristate, ethyl palmitate,
ethyl oleate, ethyl elaidate, ethyl linoleate, ethyl linolenate,
ethyl stearate, ethyl erucate, ethyl ricinoleate, ethyl lincanate,
ethyl elaeostearate, ethyl arachidonate, ethyl clupanodonate,
propyl laurate, propyl myristate, propyl palmitate, propyl oleate,
propyl elaidate, propyl linoleate, propyl linolenate, propyl
stearate, propyl erucate, propyl ricinoleate, propyl licanate,
propyl elaeostearate, propyl arachidonate, propyl clupanodonate,
isopropyl laurate, isopropyl myristate, isopropyl palmitate,
isopropyl oleate, isopropyl elaidate, isopropyl linoleate,
isopropyl linolenate, isopropyl stearate, isopropyl erucate,
isopropyl ricinoleate, isopropyl licanate, isopropyl elaeostearate,
isopropyl arachidonate, isopropyl clupanodonate, butyl laurate,
butyl myristate, butyl palmitate, butyl oleate, butyl elaidate,
butyl linoleate, butyl linolenate, butyl stearate, butyl erucate,
butyl ricinoleate, butyl licanate, butyl elaeostearate, butyl
arachidonate, butyl clupanodonate, sec.butyl laurate, sec.butyl
myristate, sec.butyl palmitate, sec. butyl oleate, sec.butyl
elaidate, sec.butyl linoleate, sec.butyl linolenate, sec.butyl
stearate, sec.butyl erucate, sec.butyl ricinoleate, sec.butyl
licanate, sec.butyl elaeostearate, sec.butyl arachidonate,
sec.butyl clupanodonate, isobutyl laurate, isobutyl myristate,
isobutyl palmitate, isobutyl oleate, isobutyl elaidate, isobutyl
linoleate, isobutyl linolenate, isobutyl stearate, isobutyl
erucate, isobutyl ricinoleate, isobutyl licanate, isobutyl
elaeostearate, isopropyl arachidonate, isobutyl clupanodonate, amyl
laurate, amyl myristate, amyl palmitate, amyl oleate, amyl
elaidate, amyl linoleate, amyl linolenate, amyl stearate, amyl
erucate, amyl ricinoleate, amyl licanate, amyl elaeostearate, amyl
arachidonate, amyl clupanodonate, hexyl laurate, hexyl myristate,
hexyl palmitate, hexyl oleate, hexyl elaidate, hexyl linoleate,
hexyl linolenate, hexyl stearate, hexyl erucate, hexyl ricinoleate,
hexyl licanate, hexyl elaeostearate, hexyl arachidonate, hexyl
clupanodonate, heptyl laurate, heptyl myristate, heptyl palmitate,
heptyl oleate, heptyl elaidate, heptyl linoleate, heptyl
linolenate, heptyl stearate, heptyl erucate, heptyl ricinoleate,
heptyl lincanate, heptyl elaeostearate, heptyl arachidonate, heptyl
clupanodonate, octyl laurate, octyl myristate, octyl palmitate,
octyl oleate, octyl elaidate, octyl linoleate, octyl linolenate,
octyl stearate, octyl erucate, octyl ricinoleate, octyl licanate,
octyl elaeostearate, octyl arachidonate, octyl clupanodonate,
2-ethylhexyl laurate, 2-ethylhexyl myristate, 2-ethylhexyl
palmitate, 2-ethylhexyl oleate, 2-ethylhexyl elaidate, 2-ethylhexyl
linoleate, 2-ethylhexyl linolenate, 2-ethylhexyl stearate,
2-ethylhexyl erucate, 2-ethylhexyl ricinoleate, 2-ethylhexyl
licanate, 2-ethylhexyl elaeostearate, 2-ethylhexyl arachidonate,
2-ethylhexyl clupanodonate, t-butyl laurate, t-butyl myristate,
t-butyl palmitate, t-butyl oleate, t-butyl elaidate, t-butyl
linoleate, t-butyl linolenate, t-butyl stearate, t-butyl erucate,
t-butyl ricinoleate, t-butyl licanate, t-butyl elaeostearate,
t-butyl arachidonate, t-butyl clupanodonate, isooctyl laurate,
isooctyl myristate, isooctyl palmitate, isooctyl oleate, isooctyl
elaidate, isooctyl linoleate, isooctyl linolenate, isooctyl
stearate, isooctyl erucate, isooctyl ricinoleate, isooctyl
licanate, isooctyl elaeostearate, isooctyl arachidonate, isooctyl
clupanodonate, nonyl laurate, nonyl myristate, nonyl palmitate,
nonyl oleate, nonyl elaidate, nonyl linoleate, nonyl linolenate,
nonyl stearate, nonyl erucate, nonyl ricinoleate, nonyl licanate,
nonyl elaeostearate, nonyl arachidonate, nonyl clupanodonate, decyl
laurate, decyl myristate, decyl palmitate, decyl oleate, decyl
elaidate, decyl linoleate, decyl linolenate, decyl stearate, decyl
erucate, decyl ricinoleate, decyl licanate, decyl elaeostearate,
decyl arachidonate, decyl clupanodonate, undecyl laurate, undecyl
myristate, undecyl palmitate, undecyl oleate, undecyl elaidate,
undecyl linoleate, undecyl linolenate, undecyl stearate, undecyl
erucate, undecyl ricinoleate, undecyl licanate, undecyl
elaeostearate, undecyl arachidonate, undecyl clupanodonate, dodecyl
laurate, dodecyl myristate, dodecyl palmitate, dodecyl oleate,
dodecyl elaidate, dodecyl linoleate, dodecyl linolenate, dodecyl
stearate, dodecyl erucate, dodecyl ricinoleate, dodecyl licanate,
dodecyl elaeostearate, dodecyl arachidonate, dodecyl clupanodonate,
methyl brasidate, ethyl brasidate, propyl brasidate, isopropyl
brasidate, butyl brasidate, sec-butyl braisidate, isobutyl
brasidate, t-butyl brasidate, amyl brasidate, hexyl brasidate,
heptyl brasidate, octyl brasidate, 2-ethylhexyl brasidate, isooctyl
brasidate, nonyl brasidate, decyl brasidate, undecyl brasidate,
dodecyl brasidate, hydroxyethyl laurate, hydroxyethyl myristate,
hydroxyethylpalmitate, hydroxyethyl oleate, hydroxyethyl elaidate,
hydroxyethyl linoleate, hydroxyethyl linolenate, hydroxyethyl
stearate, hydroxyethyl erucate, hydroxyethyl ricinoleate,
hydroxyethyl licanate, hydroxyethyl elaeostearate, hydroxyethyl
arachidonate, hydroxyethyl clupanodonate, hydroxyethyl brasidate,
polyethoxylated lauric acid, polyethoxylated myristic acid,
polyethoxylated palmitic acid, polyethoxylated oleic acid,
polyethoxylated elaidic acid, polyethoxylated linoleic acid,
polyethoxylated linolenic acid, polyethoxylated stearic acid,
polyethoxylated erucic acid, polyethoxylated ricinoleic acid,
polyethoxylated licanic acid, polyethoxylated elaeostearic acid,
polyethoxylated arachidonic acid, polyethoxylated clupanodonic
acid, polyethoxylated brasidic acid, hydroxpropyl laurate,
hydroxypropyl myristate, hydroxypropyl palmitate, hydroxypropyl
oleate, hydroxypropyl elaidate, hydroxypropyl linoleate,
hydroxypropyl linolenate, hydroxypropyl stearate, hydroxypropyl
erucate, hydroxypropyl ricinoleate, hydroxypropyl licanate,
hydroxypropyl elaeostearate, hydroxypropyl arachidonate,
hydroxypropyl clupanodonate, hydroxypropyl brasidate,
polypropoxylated lauric acid, polypropoxylated myristic acid,
polypropoxylated palmitic acid, polypropoxylated oleic acid,
polypropoxylated elaidic acid, polypropoxylated linoleic acid,
polypropoxylated linolenic acid, polypropoxylated stearic acid,
polypropoxylated erucic acid, polypropoxylated ricinoleic acid,
polypropoxylated licanic acid, polypropoxylated elaeostearic acid,
polypropoxylated arachidonic acid, polypropoxylated clupanodonic
acid, polypropoxylated brasidic acid, cyclopentyl laurate,
cyclopentyl myristate, cyclopentyl palmitate, cyclopentyl oleate,
cyclopentyl elaidate, cyclopentyl linoleate, cyclopentyl
linolenate, cyclopentyl stearate, cyclopentyl erucate, cyclopentyl
ricinoleate, cyclopentyl licanate, cyclopentyl elaeostearate,
cyclopentyl arachidonate, cyclopentyl clupanodonate, cyclopentyl
brasidate, cyclohexyl laurate, cyclohexyl myristate, cyclohexyl
palmitate, cyclohexyl oleate, cyclohexyl elaidate, cyclohexyl
linoleate, cyclohexyl linolenate, cyclohexyl stearate, cyclohexyl
erucate, cyclohexyl ricinoleate, cyclohexyl licanate, cyclohexyl
elaeostearate, cyclohexyl arachidonate, cyclohexyl clupanodonate,
cyclohexyl brasidate, methoxyethyl laurate, methoxyethyl myristate,
methoxyethyl palmitate, methoxyethyl oleate, methoxyethyl elaidate,
methoxyethyl linoleate, methoxyethyl linolenate, methoxyethyl
stearate, methoxyethyl erucate, methoxyethyl ricinoleate,
methoxyethyl licanate, methoxyethyl elaeostearate, methoxyethyl
arachidonate, methoxyethyl clupanodonate, methoxyethyl brasidate,
isopropoxyethyl laurate, isopropoxyethyl myristate, isopropoxyethyl
palmitate, isopropoxyethyl oleate, isopropoxyethyl elaidate,
isopropoxyethyl linoleate, isopropoxyethyl linolenate,
isopropoxyethyl stearate, isopropoxyethyl ercuate, isopropoxyethyl
ricinoleate, isopropoxyethyl licanate, isopropoxyethyl
elaeostearate, isopropoxyethyl arachidonate, isopropoxyethyl
clupanodonate, isopropoxyethyl brasidate, butoxyethyl laurate,
butoxyethyl myristate, butoxyethyl palmitate, butoxyethyl oleate,
butoxyethyl elaidate, butoxyethyl linoleate, butoxyethyl
linolenate, butoxyethyl stearate, butoxyethyl erucate, butoxyethyl
elaeostearate, butoxyethyl licanate, butoxyethyl ricinoleate,
butoxyethyl arachidonate, butoxyethyl clupanodonate, butoxyethyl
brasidate, methoxypropyl laurate, methoxypropyl myristate,
methoxypropyl palmitate, methoxypropyl oleate, methoxypropyl
elaidate, methoxypropyl linoleate, methoxypropyl linolenate,
methoxypropyl stearate, methoxypropyl erucate, methoxypropyl
ricinoleate, methoxypropyl licanate, methoxypropyl elaeostearate,
methoxypropyl arachidonate, methoxypropyl clupanodonate,
methoxypropyl brasidate, ethoxypropyl laurate, ethoxypropyl
myristate, ethoxypropyl palmitate, ethoxypropyl oleate,
ethoxypropyl elaidate, ethoxypropyl linoleate, ethoxypropyl
linolenate, ethoxypropyl stearate, ethoxypropyl erucate,
ethoxypropyl ricinoleate, ethoxypropyl licanate, ethoxypropyl
elaeostearate, ethoxypropyl arachidonate, ethoxypropyl
clupanodonate, ethoxypropyl brasidate, butoxypropyl laurate,
butoxypropyl myristate, butoxypropyl palmitate, butoxypropyl
oleate, butoxypropyl elaidate, butoxypropyl linoleate, butoxypropyl
linolenate, butoxypropyl stearate, butoxypropyl erucate,
butoxypropyl ricinoleate, butoxypropyl licanate, butoxypropyl
elaeostearate, butoxypropyl arachidonate, butoxypropyl
clupanodonate, butoxypropyl brasidate, isopropoxypropyl laurate,
isopropoxypropyl myristate, isopropoxypropyl palmitate,
isopropoxypropyl oleate, isopropoxypropyl elaidate,
isopropoxypropyl linoleate, isopropoxypropyl linolenate,
isopropoxypropyl stearate, isopropoxypropyl erucate,
isopropoxypropyl ricinoleate, isopropoxypropyl licanate,
isopropoxypropyl elaeostearate, isopropoxypropyl arachidonate,
isopropoxypropyl clupanodonate, isopropoxypropyl brasidate, and the
like.
[0067] Examples of fats and oils are selected from the group
consisting of animal fat, beef tallow, borneo tallow, butterfat,
camelina oil, candlefish oil, canola oil, castor oil, cocoa butter,
cocoa butter substitutes, coconut oil, cod-liver oil, coriander
oil, corn oil, cottonseed oil, flax oil, hazelnut oil, hempseed
oil, herring oil, illipe fat, jatropha oil, kokum butter, lanolin,
lard, linseed oil, mango kernel oil, marine oils, meadowfoam oil,
menhaden oil, milk fat, mowrah fat, mustard oil, mutton tallow,
neat's foot oil, olive oil, orange roughy oil, palm oil, palm
kernel oil, palm kernel olein, palm kernel stearin, palm olein,
palm stearin, peanut oil, phulwara butter, pile herd oil, rapeseed
oil, rice bran oil, safflower oil, sal fat, sardine oil, sasanqua
oil, shea fat, shea butter, soybean oil, sunflower seed oil, tall
oil, tallow, tsubaki oil, rung oil, vegetable oil, whale oil,
triacylglycerols, diacylglycerols, monoacylglycerols, triolein,
triglycerides of medium chain fatty acids, and derivatives,
conjugated derivatives, genetically-modified derivatives and
mixtures thereof. Other sources of suitable fatty acids include
used cooking oils, float grease from wastewater treatment plants,
animal fats such as beef tallow and pork lard, crude oils, "yellow
grease," i.e., animal or vegetable oils and fats that have been
used or generated as a result of the preparation of food by a
restaurant or other food establishment that prepares or cooks food
for human consumption with a free fatty acid content of less than
15%, and white grease, i.e., rendered fat derived primarily from
pork, and/or other animal fats.
[0068] In one embodiment, the substrate for ozonolysis can be
soluble or substantially soluble or suspendable in liquid CO2. Some
examples can include propylene, 1-butene, cyclopentene,
cyclohexene, cycloheptene, cyclooctene, cis-stilbene,
trans-stilbene, and similar types of compounds.
[0069] However, some of the substrates that may be desired to be
reacted through ozonolysis may not be soluble in either carbon
dioxide or carbon dioxide-expanded liquids. Such immiscible liquid
phases are not uncommon in industrial processes. In such cases, the
interfacial surface area can be increased to overcome the mass
transfer limitations, and thereby enhance the reaction rate. The
interfacial surface area can be increased by intense agitation
either with a mechanical stirrer or an ultrasonic mixing device,
either of which creates an emulsion or dispersion of the substrate
in the solvent phase. Other means for intense agitation can also be
used to increase the interfacial surface. Thus, the present
invention can be used in reactions where the substrate is not
completely soluble in the solvent. This is particularly true of
important substrates from biomass including many components of
bio-oils of the many kinds described herein.
III. Catalysis
[0070] As shown in FIGS. 1A and IB, the reaction with the substrate
to obtain a desired product may occur in two steps. The first step
is ozonolysis in CO.sub.2 or CO.sub.2 expanded liquids (i.e., CXL),
as described herein. The second step in the overall process may be
catalytic or stoichiometric depending on the specific case under
development. For example, it is reported that hydrolysis of the
trioxolane will produce the corresponding dicarboxylic acids, and
that hydrolysis in the presence of a mild reductant will produce
the aldehydes. Examination of the balanced equations reveals that
simple use of the states of oxidation in the trioxolane will
produce one mole of ketone/aldehyde and one mole of carboxylic
acid. In fact, gentle reduction during cleavage of the trioxolane
will convert both emerging moieties to aldehydes while oxidative
cleavage will produce two moles of carboxylic acid. Strong
reduction will yield two moles of alcohol. Thus, new catalytic
processes can be used for the second step in ozonolysis or
ozone-based conversion of unsaturated acids and their esters into
useful, lower molecular weight products.
[0071] In one embodiment, the first and/or second step of the
ozonolysis process can be performed with a catalytic system. Known
catalytic systems are not effective at accelerating the use of the
full oxidizing power of ozone in reactions in general and in the
cleavage of carbon-carbon double bonds in particular. Catalysis of
the initial oxidation process by a transition metal catalyst can
moderate the oxidative power of the ozone. Catalysts generally
moderate ozone in two ways; by elimination of the mechanistic
pathways available to the ozone molecule, and, because of the
apparent conversion of ozone into hydroxyl radical plus less
reactive products, the selectivity of the oxidant is lost and the
yields of desired products are diminished. In the absence of
catalysts, ozone converts carbon-carbon double bond groups into
meta-stable intermediates, 1,2,4-trioxolanes, that are well-suited
to efficient second steps (solvolysis, oxidation, reduction) that
may lead to a readily selected array of desirable products.
However, the desirability of catalysis in the second step, the
transformation of the 1,2,4-ozonide to desirable products, can be
improved by catalysis, whether it be oxidation or reduction.
Accordingly, catalysts can be used with the ozonolysis of
substrates in CO.sub.2 and CXLs as described herein. Examples of
some catalysis can include, with a view toward using transition
metal ions as catalysts, iron(III) oxide, iron, cobalt, nickel,
copper, manganese, chromium, manganese (e.g., Mn(III) not Mn(VII)),
osmium, ruthenium and rhenium, manganese porphyrins, manganese
centered polyoxometallates, titanium, TiO.sub.2, combinations
thereof, oxides thereof, and the like.
IV. Ozone Purification
[0072] Additionally, the present invention provides process and
reaction conditions for preparing ozone or increasing ozone purity.
Ozone can be present in a gas, such as air or oxygen, or can be
separated therefrom. Ozone generation is well known in the art. The
ozone is often accompanied by the gas from which it was generated.
Now, the ozone can be selectively purified from the original
gas.
[0073] In one embodiment, the ozone can be separated from oxygen or
air in the presence of CO.sub.2 or CXL by increasing the pressure
of the system at a temperature close to the T.sub.c of ozone. That
is, the same conditions for increasing ozone concentration in
CO.sub.2 or CXL can be used for purifying ozone from the gas. As
such, the CO.sub.2 or CXL compositions in the presence of ozone can
be modulated by increasing pressure at a temperature close to the
Tc without a substrate. The lack of a substrate allows the O.sub.3
to be separated from either an O.sub.2+O.sub.3 or an O.sub.3+air
stream by being concentrated in the CO.sub.2 or CXL without
reacting and degrading the ozone. The separation process can be
performed by cooling the O.sub.2/air+O.sub.3 mixtures just below
the critical temperature of O.sub.3 (e.g., -12.degree. C. or 261.15
K) in order to condense out the O.sub.3 by simply increasing the
system pressure (e.g., a few tens of bars close to the critical
pressure of O.sub.3). This method can be cheaper and easier than
refrigeration techniques to separate O.sub.3.
[0074] After the concentration of ozone is increased in CO.sub.2 or
CXL, all of the gas not in the liquid can be removed. The ozone gas
in the liquid can then be separated from the liquid so as to obtain
purified ozone.
Experimental
[0075] 1.
[0076] The ozone concentration measurements and the ozonolysis
experiments were performed using a 10 cm.sup.3 titanium high
pressure view cell. A schematic representation of the reactor
system 10 is shown in FIG. 3. The reactor system 10 is shown to
include a high pressure reaction cell 12 that is cylindrical in
shape, but can be in any other shape. The cell 12 is fitted with
view window 14, such as sapphire windows at both ends, which are
sealed with PEEK O-rings and screw caps (not shown). A
spectrophotometer (not shown) (e.g., Ocean Optics fiber optic
UV/Visible spectrophotometer) is used to measure UV/Visible spectra
via the sapphire windows 14. The body of the cell 12 is fitted with
a port for ozone input 16, a port for CO.sub.2 and/or CXL input 18,
a port for a thermocouple 22 input 20, a port for a pressure
transducer 26 input 24, and a port 28 for a safety rupture disk 30.
The ozone input 16 can be fitted with a titanium frit (not shown)
to ensure good mixing of the ozone with the contents of the cell
12. Samples can be withdrawn from either the liquid or gas phase
via any of the ports. Mixing is performed using a magnetic stirrer
bar (not shown) and temperature adjustments made using a
circulating fluid thermal jacket (not shown) in contact with the
cell 12. Temperature was monitored with the thermocouple 22, and
controlled and recorded using a computer controlled data
acquisition system 32 (Dasylab, measX GmbH & Co.KG). Pressure
was monitored with the pressure transducer 26, and controlled and
recorded using the computer controlled data acquisition system
32.
[0077] Ozone is generated by an ozone generator 34 (e.g.,
Praxair-Trailgaz Unizone.TM. Lo corona discharge ozone generator)
from either a compressed air or oxygen source. The ozone containing
gas stream 36 is then led to a pump 38 (e.g., Teledyne ISCO 500D
syringe pump) where the ozone-containing stream fills the feed
reservoir 40. The reservoir 40 contents are compressed to a
pressure suitable for introduction into the reaction cell 12.
Excess ozone is destroyed by passing the exiting gas stream over a
magnesium oxide catalyst packed tube 42 followed by bubbling
through an aqueous sodium hydroxide solution 44. The bottom left
input port 18 is used to introduce carbon dioxide from a carbon
dioxide source 46 and/or nitrogen from a nitrogen source 48 into
the reaction cell 12, and also to remove products at the end of a
reaction cycle. Products are collected by bubbling the product
stream through a chilled solvent 50. The top port 28 houses a
rupture disk 30 and can also be used for product collection.
2.
[0078] To guide the experiments in CO.sub.2-expanded solvents, the
miscibility and volumetric expansion of the following mixtures in
dense CO.sub.2 can be determined in a Jurgeson.RTM. view cell at
typical operating temperatures (10-25.degree. C. or 282.15-298.15
K). Description of the Jurgeson.RTM. view cell and the experimental
procedure for measuring the volumetric expansion are given
elsewhere (Ghezai Musie, Ming Wei, Bala Subramaniam, and Daryle H.
Busch, "Catalytic Oxidations in Carbon Dioxide-based Reaction
Media, including novel CO.sub.2-expanded phases," Coord. Chem.
Revs., 219-221, 789-820 (2001); Ming Wei, Ghezai T. Musie, Daryle
H. Busch and Bala Subramaniam,"CO.sub.2-expanded Solvents: Unique
and Versatile Media for Performing Homogeneous Catalytic
Oxidations," J. Am. Chem. Soc., 124, 2513-17 (2002)).
3.
[0079] Experiments were performed to determine liquid-phase O.sub.3
concentrations. In a typical experiment to determine ozone
concentration in liquid CO.sub.2, a quantity of CO.sub.2 is
introduced into the cell (maintained at a desired temperature) via
one of the ports to a pressure at which CO.sub.2 forms a liquid
phase and the cell pressure noted. The liquid level in the cell
reaches above the windows allowing a complete path for a UV/Visible
light spectrum through the liquid phase. The gas output
(O.sub.2/O.sub.3 mixture) from the ozone generator is compressed
using the ISCO syringe pump to a pressure above the cell pressure.
The ozone containing mixture is then allowed to enter the cell
through an inlet port and allowed to equilibriate before a
UV/Visible spectrum of the liquid phase CO.sub.2 is measured. More
ozone is added repeatedly and a UV/Visible spectrum measured after
each addition, following equilibration, until the maximum desired
pressure is reached.
[0080] Ozone has two absorption bands in the UV/Visible region; a
strong band with .lamda..sub.max-253.7 nm and a weaker band with
two maxima at 577 nm and 603 nm (FIGS. 4A and 4B, respectively).
The intensity of the light absorbed by ozone at these wavelengths
is directly proportional to the concentration of the ozone, and
therefore absorption values can be used as a measure of the ozone
concentration. The Chappuis band in the visible region was chosen
because its intensity gave suitable absorption values at the ozone
concentrations studied.
[0081] The absorbance at 580 nm was measured for a solution of
ozone in liquid carbon dioxide (T=5.0.+-.0.2.degree. C. or
277.15.+-.0.2 K, P=63.4.+-.1.4 bar). A known volume (0.52 mL) of
this solution was then sampled in a stainless steel tube (FIG. 3).
This sample was allowed to expand slowly to room temperature and
pressure (R.T.P.) and the escaping gas was bubbled through an
aqueous solution of potassium iodide. The tubing was then flushed
with compressed air, which was also bubbled through a KI solution.
The KI solution was titrated with 4.times.10.sup.-4 mol dm.sup.-3
Na.sub.2S.sub.2O.sub.3 to determine the iodine concentration. The
slight drop in cell pressure was compensated for by pumping in more
O.sub.3/O.sub.2 gas mixture and the procedure was repeated three
times. Values of s are shown in Table 1.
TABLE-US-00001 TABLE 1 Concentration O.sub.3 in 0.52 ml sample Abs.
at .epsilon. Run (mol dm.sup.-3) 580 nm (dm.sup.3 mol.sup.-1
cm.sup.-1) 1 2.11 .times. 10.sup.-3 0.159 29.6 2 1.69 .times.
10.sup.-3 0.137 25.4 3 3.02 .times. 10.sup.-3 0.201 26.2 4 2.98
.times. 10.sup.-3 0.184 24.3
4.
[0082] When the gaseous output of the ozone generator is compressed
into the reaction cell using the syringe pump, the concentration of
ozone increases linearly with the total pressure (assuming ideal
gas behavior at the ISCO pump conditions). Since the mole fraction
of ozone in the output stream is constant, P.sub.O.sub.3 should
increase proportionally with the total pressure. This behavior is
confirmed in FIGS. 5 and 6 for both O.sub.2 and air as source gases
for ozone production.
5.
[0083] When measuring the concentration of ozone dissolved in
liquid carbon dioxide at -0.7.degree. C. (or 272.45 K), such linear
behavior is not observed (FIGS. 7 and 8). A volume of liquid
CO.sub.2 is introduced into the cell so that the gas/liquid
interface is sufficiently high in the cell and the light path of
the spectrophotometer is in the liquid phase throughout the
experiments. The gas output from the ozone generator is then
compressed using the syringe pump and the ozone mixture is pumped
into the liquid carbon dioxide through a titanium frit to ensure
good mixing. The ozone concentration in the liquid CO.sub.2 is then
measured spectrophotometrically after allowing a period of time for
equilibrium to be reached. As the critical pressure of ozone is
approached (808 psi, 55.7 bar), there is a significant increase in
the quantity of ozone dissolved in the liquid carbon dioxide. At
53.1 bar, the ozone concentration in the liquid phase is
approximately 0.005 unit. At 62.1 bar however, the O.sub.3
concentration in the liquid phase is 0.05 unit, dramatically
enhanced by more than order of magnitude. Similar behavior is
observed over a range of temperatures.
6.
[0084] The use of CXLs has many advantages over the use of
conventional neat solvents. By replacing a significant fraction of
conventional organic solvents with carbon dioxide, the CXL mixtures
enhance mass transfer and reaction rates, reduce waste, and make
reactors inherently safer. Additionally, many classes of substrates
have higher solubility in CXLs than in pure liquid or supercritical
carbon dioxide. A CXL is created by expanding a conventional
solvent with pressurized carbon dioxide to create a single phase
mixture in which a measurable fraction of the liquid volume is
attributable to the compressed carbon dioxide. The photograph data
(not shown) indicate that the expansion of methanol to form a CXL.
The meniscus shows that the total volume has increased by
approximately 120% under these conditions (52.7 bar of carbon
dioxide).
7.
[0085] The effect of temperature on CO.sub.2 expansion of a
methanol/soybean oil binary composition was studied. The CO.sub.2
was used to expand a 6:1 methanol soybean binary composition at
296.15 K, 323.15 K and 338.15 K. As shown in FIG. 9, the
temperature at 296 K had a more significant change in V/Vo as the
pressure was increased. The miscibility of CO.sub.2 with the
methanol+soybean binary mixture provides the opportunity to seek
enhanced ozone solubility and safe selective biomass oxidation in
this CXL system, as indicated above.
8.
[0086] Utilizing the advantages of CXLs for ozonolysis reactions is
an attractive goal. However, studies have demonstrated that the
choice of solvent to be expanded with carbon dioxide is important,
since the reactivity of ozone is such that it will rapidly oxidize
many organic solvents at the elevated pressures required to form
the CXL. When ozone is added to CO.sub.2 expanded methanol the
characteristic ozone bands in the UV/Visible spectra are not
observed (FIG. 10). The same observation is made when ozone is
added to a hexane CXL (FIG. 11). It has been widely reported,
however, that ozonolysis reactions can be conducted in organic
solvents, particularly methanol. Our attempts to measure ozone
concentrations in neat methanol at 1.013 bar and -4.degree. C.
(268.15 K) show no measurable concentration of dissolved ozone in
the solvent (FIG. 12; T=276.15 K, P=1.013 bar, 1500 mL ozone
solution 50%, 1.0 A; O.sub.2 source @ 200 cfm, ozone bubbled
through solvent). Furthermore, addition of the substrate methyl
oleate to a sample of methanol through which ozone had been
bubbled, showed no evidence of reaction (FIG. 13). However, the
UV/Visible spectra (FIG. 14; T=276.15 K, P=1.013 bar, 0.5 mL methyl
oleate in 9 mL methanol) taken following the addition of ozone to a
methanolic solution of methyl oleate, indicate the formation of a
product with a strong absorption band in the UV region
(.lamda..sub.max=284 nm). These observations indicate that ozone
readily oxidizes methanol, but, kinetically, the reaction with
methyl oleate is preferred. This can provide an indication that the
substrate that is the solvent can be the target of ozone oxidation
(e.g., methyl oleate as the substrate and solvent).
9.
[0087] Ozonolysis experiments were conducted on various substrates.
In a typical substrate ozonolysis experiment, the substrate is
introduced into the reaction cell maintained at ambient pressure
and the desired reaction temperature, following which CO.sub.2 is
added to create a liquid phase. Using the ISCO pump, the ozone
containing gas is then pumped into the reaction cell to a
predetermined pressure above that of the CO.sub.2/substrate
mixture. The ozone concentration is followed spectrophotometrically
during the reaction. At the end of the batch reaction, samples are
withdrawn from the CO.sub.2 liquid phase by depressurizing the
effluent to a cold trap (maintained at -78.degree. C. or 195.15 K)
in which the samples are collected and subsequently analyzed using
GC/MS.
10.
[0088] The concentration of ozone dissolved in water was measured
using UV/Visible spectrophotometry as increasing pressures of a
gaseous mixture of O.sub.2 and O.sub.3 were applied. The intensity
of the light absorbed by ozone at 580 nm is directly proportional
to the concentration of the ozone and therefore absorption values
can be used as a measure of the ozone concentration. In a typical
measurement, water was introduced into the view cell so that the
gas liquid interface was well above the light path of the Ocean
Optics Fiber Optic spectrophotometer. The cell was then sealed and
the temperature allowed to equilibrate. Temperature was controlled
using a refrigerated bath circulating a heat transfer fluid through
an aluminum jacket in thermal contact with the view cell. The
gaseous output of the ozone generator was then compressed and
pumped into the view cell using the ISCO syringe pump.
Spectrophotometric measurements were taken as the pressure was
increased. After each increase in pressure, the cell contents were
thoroughly stirred, using a magnetic stirrer bar, for at least two
minutes before a spectrophotometric measurement was taken.
[0089] The spectra recorded at a series of pressures and
temperatures (FIGS. 15, 16, and 17) clearly show that the
concentration of ozone dissolved in water increases linearly as a
function of pressure. There is no sharp enhancement of ozone
concentration in water, as there is in liquid carbon dioxide, as
the pressure increases through the critical pressure of ozone (808
psi, 55.7 bar).
11.
[0090] In a typical experiment, a known quantity of the olefinic
substrate was placed in a high pressure reaction cell and carbon
dioxide was added to a pressure of 44.8 bar. The solution was
cooled to the reaction temperature and then a gaseous mixture of
ozone and oxygen was added to the reaction cell using an ISCO
syringe pump until at least a twofold excess of ozone had been
added. The mixture was left to react, with stirring, for several
hours. Product collection was performed by slowly venting the
liquid CO.sub.2 portion of the mixture through a cold (0.degree. C.
or 273.15 K) trap consisting of methanol, hexane or
dichloromethane. The cell was then re-pressurized with CO.sub.2 and
vented through the trap a second time. The cell was then washed
twice with the collection solvent. Product analysis was performed
by GC/MS with relevant internal standards. Major products for each
substrate studied are shown in Table 2.
TABLE-US-00002 TABLE 2 Substrate Mixing Conversion Products methyl
oleate mechanical 24% nonanal (insoluble in nonanedioic acid,
liquid CO.sub.2) monomethyl ester nonanoic acid methyl oleate
ultrasonic 100% nonanal 9-oxo-nonanoic acid, methyl ester
nonanedioic acid, monomethyl ester nonanoic acid trans- stilbene
mechanical 95% benzaldehyde, (soluble in benzoic acid, liquid
CO.sub.2) benzoic acid, ethyl ester phenol 2-hexanone cis-stilbene
mechanical 85% benzaldehyde (soluble in benzoic acid liquid
CO.sub.2) phenol cyclohexene mechanical 99% polymer hexanoic acid
1,1'oxybis(hexane) propylene mechanical polymer acetic acid
cyclopentanol ferulic acid ultrasonic >80% 4-hydroxy-3-methoxy-
benzaldehyde phenol
[0091] As shown in FIG. 18, a high pressure reaction system 60 was
constructed. The high pressure reaction system 60 can include many
of the features shown in FIG. 3. The high pressure reaction system
60 additionally includes a high pressure titanium reaction cell 62,
incorporating an ultrasonic probe 64 (FIG. 18). The ultrasonic
probe 64 extends into the reaction cell 62 and is coupled thereto
with a retaining plate 66. The retaining plate is further coupled
to an ultrasonic transducer 68 that receives high frequency input
from a signal generator 70 for the ultrasonic probe 64.
[0092] The reaction system 60 was used to create emulsions of
insoluble substrate in liquid CO.sub.2 in order to enhance the
interphase mass transfer area for reaction between the substrate
and O.sub.2. The stability of ozone, when ozone-containing
solutions were subjected to ultrasonic mixing, was also
investigated.
[0093] In water, ultrasonic agitation was shown to increase the
rate of ozone decomposition by at least two orders of magnitude as
shown in FIG. 19 (Kang, J-W., Lee, K-H., Koh, C-L, Nam, S-N.,
Korean Journal of Chemical Engineering 18 336 (2001)). Our research
has shown that there is no such effect using dense phase carbon
dioxide (FIG. 20), probably due to the absence of the free radical
propagation steps typical of the mechanism of ozone decomposition
in water.
[0094] The present invention may be embodied in other specific
forms without departing from its spirit or essential
characteristics. The described embodiments are to be considered in
all respects only as illustrative and not restrictive. The scope of
the invention is, therefore, indicated by the appended claims
rather than by the foregoing description. All changes which come
within the meaning and range of equivalency of the claims are to be
embraced within their scope. All references recited herein are
incorporated herein in their entirety by specific reference.
[0095] The present disclosure is not to be limited in terms of the
particular embodiments described in this application, which are
intended as illustrations of various aspects. Many modifications
and variations can be made without departing from its spirit and
scope, as will be apparent to those skilled in the art.
Functionally equivalent methods and apparatuses within the scope of
the disclosure, in addition to those enumerated herein, will be
apparent to those skilled in the art from the foregoing
descriptions. Such modifications and variations are intended to
fall within the scope of the appended claims. The present
disclosure is to be limited only by the terms of the appended
claims, along with the full scope of equivalents to which such
claims are entitled. It is to be understood that this disclosure is
not limited to particular methods, reagents, compounds compositions
or biological systems, which can, of course, vary. It is also to be
understood that the terminology used herein is for the purpose of
describing particular embodiments only, and is not intended to be
limiting.
[0096] With respect to the use of substantially any plural and/or
singular terms herein, those having skill in the art can translate
from the plural to the singular and/or from the singular to the
plural as is appropriate to the context and/or application. The
various singular/plural permutations may be expressly set forth
herein for sake of clarity.
[0097] It will be understood by those within the art that, in
general, terms used herein, and especially in the appended claims
(e.g., bodies of the appended claims) are generally intended as
"open" terms (e.g., the term "including" should be interpreted as
"including but not limited to," the term "having" should be
interpreted as "having at least," the term "includes" should be
interpreted as "includes but is not limited to," etc.). It will be
further understood by those within the art that if a specific
number of an introduced claim recitation is intended, such an
intent will be explicitly recited in the claim, and in the absence
of such recitation no such intent is present. For example, as an
aid to understanding, the following appended claims may contain
usage of the introductory phrases "at least one" and "one or more"
to introduce claim recitations. However, the use of such phrases
should not be construed to imply that the introduction of a claim
recitation by the indefinite articles "a" or "an" limits any
particular claim containing such introduced claim recitation to
embodiments containing only one such recitation, even when the same
claim includes the introductory phrases "one or more" or "at least
one" and indefinite articles such as "a" or "an" (e.g., "a" and/or
"an" should be interpreted to mean "at least one" or "one or
more"); the same holds true for the use of definite articles used
to introduce claim recitations. In addition, even if a specific
number of an introduced claim recitation is explicitly recited,
those skilled in the art will recognize that such recitation should
be interpreted to mean at least the recited number (e.g., the bare
recitation of "two recitations," without other modifiers, means at
least two recitations, or two or more recitations). Furthermore, in
those instances where a convention analogous to "at least one of A,
B, and C, etc." is used, in general such a construction is intended
in the sense one having skill in the art would understand the
convention (e.g., "a system having at least one of A, B, and C"
would include but not be limited to systems that have A alone, B
alone, C alone, A and B together, A and C together, B and C
together, and/or A, B, and C together, etc.). In those instances
where a convention analogous to "at least one of A, B, or C, etc."
is used, in general such a construction is intended in the sense
one having skill in the art would understand the convention (e.g.,
"a system having at least one of A, B, or C" would include but not
be limited to systems that have A alone, B alone, C alone, A and B
together, A and C together, B and C together, and/or A, B, and C
together, etc.). It will be further understood by those within the
art that virtually any disjunctive word and/or phrase presenting
two or more alternative terms, whether in the description, claims,
or drawings, should be understood to contemplate the possibilities
of including one of the terms, either of the terms, or both terms.
For example, the phrase "A or B" will be understood to include the
possibilities of "A" or "B" or "A and B.
[0098] In addition, where features or aspects of the disclosure are
described in terms of Markush groups, those skilled in the art will
recognize that the disclosure is also thereby described in terms of
any individual member or subgroup of members of the Markush
group.
[0099] As will be understood by one skilled in the art, for any and
all purposes, such as in terms of providing a written description,
all ranges disclosed herein also encompass any and all possible
subranges and combinations of subranges thereof. Any listed range
can be easily recognized as sufficiently describing and enabling
the same range being broken down into at least equal halves,
thirds, quarters, fifths, tenths, etc. As a non-limiting example,
each range discussed herein can be readily broken down into a lower
third, middle third and upper third, etc. As will also be
understood by one skilled in the art all language such as "up to,"
"at least," "greater than," "less than," and the like include the
number recited and refer to ranges which can be subsequently broken
down into subranges as discussed above. Finally, as will be
understood by one skilled in the art, a range includes each
individual member. Thus, for example, a group having 1-3 cells
refers to groups having 1, 2, or 3 cells. Similarly, a group having
1-5 cells refers to groups having 1, 2, 3, 4, or 5 cells, and so
forth."
[0100] While various aspects and embodiments have been disclosed
herein, other aspects and embodiments will be apparent to those
skilled in the art. The various aspects and embodiments disclosed
herein are for purposes of illustration and are not intended to be
limiting, with the true scope and spirit being indicated by the
following claims.
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